/Engine/Plugins/Online/OnlineSubsystemUtils/Source/OnlineSubsystemUtils/Classes/OnlineSessionClient.h
Ends an existing session of a given name
void EndExistingSession ( [FName](API\Runtime\Core\UObject\FName) SessionName, [FOnEndSessionCompleteDelegate](API\Plugins\OnlineSubsystem\Interfaces\FOnEndSessionCompleteDelegate) & Delegate )